POS0484 HIGH ANTI-CCP LEVEL AND FEMALE GENDER ARE ASSOCIATED WITH PROGRESSION TO PERSISTENT ARTHRITIS IN PATIENTS WITH PALINDROMIC RHEUMATISM; RESULTS OF A UK PROSPECTIVE COHORT STUDY
Authors: R. Chowdhury, F. Shuweihdi, N. Sidhu, L. Duquenne, L. Garcia-Montoya, J. Nam, A. DI Matteo, K. Harnden, P. Emery, K. Mankia
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Palindromic rheumatism (PR) is a recognised precursor of rheumatoid arthritis (RA) and is characterised by episodic flares of pain and swelling in and around joints <sup>[1]</sup>. Up to 50% of PR patients will progress to persistent arthritis (PA) <sup>[1]</sup>. However, PR is challenging to identify and study longitudinally and risk factors for progression remain unclear <sup>[1]</sup>. This is the first large UK prospective PR cohort study describing risk factors in patients with PR, the majority of whom were treatment naïve at baseline. <h3>Objectives</h3> To investigate baseline risk factors associated with progression to PA in PR patients. <h3>Methods</h3> Patients with suspected PR were recruited to the Leeds PR cohort from regional primary care and secondary care referrals. In the absence of an accepted classification criteria, PR was defined as 'a confirmed history or physical examination consistent with episodes of joint pain and swelling that returned to normal between episodes in the absence of an alternative diagnosis' <sup>[2]</sup>. At baseline, a comprehensive set of clinical, imaging, serological and immunogenetic parameters was assessed. Patients were monitored at 3 monthly intervals for the first year, then 6 monthly or earlier if clinically indicated. Progression to PA was defined by the presence of at least one tender and swollen joint confirmed by a rheumatologist, which persisted for at least 3 weeks. Baseline variables included in the analysis were: age, smoking status, gender, first degree relative with RA, time interval between flares, number of joints typically affected in a flare, wrist joint involvement in flares, hand joint involvement in flares, HLA DR shared epitope (SE), anti-CCP status, rheumatoid factor status and DMARD use during follow up. Cox regression analysis identified factors associated with progression to PA using the R statistical program. Model discrimination, using concordance index, was 0.741. <h3>Results</h3> 161 patients were followed between July 2008 and December 2022. 32% (51/161) of patients developed PA after a median of 12 months. 90% (46/51) of progressors met criteria for RA. 90% (145/161) of patients were DMARD naive at baseline. Cox regression showed female gender (HR 2.7, CI 1.2-6.0, p=0.01) and high anti-CCP level (&gt; 3X upper limit of normal range) (HR 6.1, CI 1.9-19, p=0.004) were associated with progression to PA. Flares in joints of the hands was found to be protective (HR 0.3, CI 0.1-0.9, p= 0.04). Typical involvement of &lt; 3 joints in flares was also protective, with a trend towards significance (HR 0.4, CI 0.1-1.0, p=0.05). The remaining variables including frequency of flares, HLA DR SE and DMARD exposure were not associated with progression status. <h3>Conclusion</h3> In patients with PR, female gender and high anti-CCP level were associated with progression to PA. Conversely, hand joint involvement and flares typically affecting &lt;3 joints were protective. These data provide novel insights into the natural history of PR and will inform a risk stratification model for monitoring and early therapeutic intervention. <h3>References</h3> [1]Mankia K et al. What can palindromic rheumatism tell us? Best Pract Res Clin Rheumatol. 2017 Feb;31(1):90-98. doi: 10.1016/j.berh.2017.09.014. Epub 2017 Oct 25. PMID: 29221602. [2]Mankia K et al. Identification of a distinct imaging phenotype may improve the management of palindromic rheumatism Annals of the Rheumatic Diseases 2019;<b>78:</b>43-50. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Rahaymin Chowdhury: None declared, Farag Shuweihdi: None declared, Navkiran Sidhu: None declared, Laurence Duquenne: None declared, Leticia Garcia-Montoya: None declared, Jacqueline Nam: None declared, Andrea Di Matteo: None declared, Kate Harnden: None declared, Paul Emery Speakers bureau: Abbvie, Gilead, Lilly, Novartis, Consultant of: BMS, AbbVie, MSD, Pfizer, Novartis, and Roche, Grant/research support from: AbbVie, BMS, Lilly, Samsung, Kulveer Mankia Speakers bureau: Abbvie, Lilly, UCB, Grant/research support from: Gilead, Lilly.